Though a rare cause of death, lightning is reported to be responsible for more fatalities each year in this country than any other type of natural disaster. Lightning injuries differ significantly from other high voltage electrical injuries because of the high current flow, but extremely short duration of the lightning strike.
Lightning can affect all organ systems, especially the cardiovascular system. The primary cause of death following a lighting strike is cardiopulmonary arrest. The current in a lightning bolt is as high as 30,000 Amperes at 1,000,000 or more Volts. The short duration of about 1-100 milliseconds limits, but does not prevent serious injury. There are several types of outdoors lightning injury. The most severe is a direct strike, either on the victim or on some object the victim is holding such as a golf club, tripod or umbrella. A “side flash” occurs when lightning hits a nearby object and jumps to the victim. Ground current injuries occur when lightning strikes the ground nearby and spreads to a victim.
Avoidance and prevention are the best means of lightning safety. The risk of a lightning related injury can be minimized with some simple safety measures but not eliminated completely. Just as remaining in a metal vehicle during lightning activity can provide protection, a protective garment that includes an electrically conductive shield can benefit someone who finds himself exposed to a potential lightning strike. What is needed is a protective garment that reduces deaths related to cardiopulmonary arrest following a lightning strike.
Applicant has found no patent nor non-patent literature expressly describing such a garment, however, U.S. Pat. No. 7,712,149 issued to Baldwin in 2010 for a “Protective Article of Outer Clothing” discloses a garment intended for protection against attack by Taser (an electrical stun gun), and suggests (at col. 4, lines 8-12) that such garment might be useful as protection against a lightning strike. The Baldwin garment provides an electrically conductive shield, but lacks any other feature that will benefit the victim of a lightning strike.
Several U.S. patents, in addition to that by Baldwin, disclose electrically conductive textiles of varying types, potentially useful for making electrically protective garments, e.g., U.S. Pat. Nos. 7,947,773, 7,832,983, 7,817,401, 7,284,280, 6,272,781, and 5,906,004. Medical information related to lightning-caused injury and death has been reported in two publications, limited portions of which are paraphrased above: (1) a publication of the Center for Disease Control, “Lightning-Associated Deaths—United States, 1980-1995”, MMWR 47 (19), at pages 391-394, May 22, 1998; and (2) a paper titled “Deaths Caused by Lightning”, by Lifschultz et al., Journal of Forensic Sciences 38 (2), at pages 353-358, March 1993.
An interesting medical study published in 1986 [“Lightning injury caused by discharges accompanying flashovers—a clinical and experimental study of death and survival”, Ohashi M., et al., in Burns Incl Therm Inj 1986 October; 12 (7): 496-501, Abstract] reported that “[d]uring the 17 years preceding March 1985, 140 patients sustained lightning injuries caused by 44 thunderbolts. Fifty patients showed evidence of current flow through their bodies. These 50 victims were classified into two groups, the first consisting of 9 victims who showed rupture of their clothes or lineal superficial dermal burns along their whole bodies from head to feet, indicating the occurrence of surface flashovers. The remaining 41 patients showed no evidence of this flash effect. It is noteworthy that in the first group 5 of the 9 survived, whereas in the second group only 6 among 41 survived. The result indicates that when a flashover occurs along the whole body, the probability of survival is higher than 50 percent. The conditions which determine death or survival were investigated experimentally, imposing artificial lightning voltage impulses on rats and developing flashovers on them. The rats survived when the voltage drop caused by flashover occurred immediately after the peak point, and the current waveform exhibited a sharp peak. In contrast, the rats were killed when the voltage drop caused by flashover was delayed by more than 20 microseconds, and the current waveform showed a blunt cone shape. It has been concluded that a fast flashover appreciably diminishes the energy dissipation within the body and consequently results in survival.”
No garment that is both practical and wearable can prevent most serious injuries resulting from a lightning strike. A victim will be severely injured. What is needed is a protective garment that can reduce the number of deaths resulting each year from cardiopulmonary arrest following a lightning strike.
It is an object of the present invention to provide a garment that can reduce the number of lightning caused deaths by effectively protecting the user's cardiopulmonary system.